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Fix parameter adjustment with dictionary

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The new advanced API basically set `requestedParams = appliedParams` when
using a dictionary. This halted all parameter adjustment, which can hurt
compression ratio if, for example, the window log is small for the first
call, but the rest of the files are large.

This patch fixes the bug, and checks that the `requestedParams` don't change
in the new advanced API when using a dictionary, and generally in the fuzzer.
This commit is contained in:
Nick Terrell
2018-04-25 16:32:29 -07:00
parent 12f60b8c98
commit ca77822ddf
2 changed files with 64 additions and 10 deletions
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lib/compress/zstd_compress.c
+6 -10
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@@ -1195,18 +1195,16 @@ void ZSTD_invalidateRepCodes(ZSTD_CCtx* cctx) {
static size_t ZSTD_resetCCtx_usingCDict(ZSTD_CCtx* cctx,
const ZSTD_CDict* cdict,
unsigned windowLog,
ZSTD_frameParameters fParams,
ZSTD_CCtx_params params,
U64 pledgedSrcSize,
ZSTD_buffered_policy_e zbuff)
{
{ ZSTD_CCtx_params params = cctx->requestedParams;
{ unsigned const windowLog = params.cParams.windowLog;
assert(windowLog != 0);
/* Copy only compression parameters related to tables. */
params.cParams = cdict->cParams;
if (windowLog) params.cParams.windowLog = windowLog;
params.fParams = fParams;
ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,
ZSTDcrp_noMemset, zbuff);
params.cParams.windowLog = windowLog;
ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize, ZSTDcrp_noMemset, zbuff);
assert(cctx->appliedParams.cParams.strategy == cdict->cParams.strategy);
assert(cctx->appliedParams.cParams.hashLog == cdict->cParams.hashLog);
assert(cctx->appliedParams.cParams.chainLog == cdict->cParams.chainLog);
@@ -2495,9 +2493,7 @@ size_t ZSTD_compressBegin_internal(ZSTD_CCtx* cctx,
assert(!((dict) && (cdict))); /* either dict or cdict, not both */
if (cdict && cdict->dictContentSize>0) {
cctx->requestedParams = params;
return ZSTD_resetCCtx_usingCDict(cctx, cdict, params.cParams.windowLog,
params.fParams, pledgedSrcSize, zbuff);
return ZSTD_resetCCtx_usingCDict(cctx, cdict, params, pledgedSrcSize, zbuff);
}
CHECK_F( ZSTD_resetCCtx_internal(cctx, params, pledgedSrcSize,